仁王經疏 3.65

3.65

釋曰：第三、二偈明空。文別有二：初有一偈明其法空。初句明所執性。下三句明依他空，謂依他上無所執性。眾生蠢蠢都如幻居者，第二一偈明生空。言聲響俱空國土亦如者，以勝劣況。謂聲及響皆於所說，非實有性，猶如聲響非實故空。國土亦爾，諸法因緣所成法故，亦說為空也。

Explanation: Third, two verses explain emptiness. The text is divided into two parts: first, one verse explains the emptiness of dharmas. The first line explains the imagined nature (parikalpita-svabhāva). The following three lines explain the emptiness of other-dependent nature (paratantra-svabhāva), meaning that upon the other-dependent, there is no imagined nature.
As for "Sentient beings, wriggling and squirming, all dwell as illusions": the second verse explains the emptiness of sentient beings (pudgala-nairātmya).
As for "Sound and echo are both empty; kingdoms are also like this": this makes a comparison using the superior and the inferior. It means that both sound and echo are as spoken, lacking real substantial nature; just as sound and echo are unreal and therefore empty, kingdoms are likewise so, because they are dharmas formed through causes and conditions, and are therefore also spoken of as empty.